Chang Liu,Yanan Wu,Mengying Li,Fang Liu,Pengfei Kong,Haifeng Yang,Xinling Liu
Salivary d-alanine (d-Ala) and d-proline (d-Pro) are of concern for their potential in the noninvasive diagnosis of gastric cancer (GC). Most reports have succeeded in determining the total concentration of d-Ala and d-Pro. However, for personalized diagnosis and better elucidation of the underlying specific correlation of d-Ala (or d-Pro) with GC, it is desirable to determine the specific concentration of d-Ala or d-Pro. Herein, we propose an enantiomer-specific tandem assay of d-Ala based on the colorimetric reaction between 2,4-dinitrophenylhydrazine and pyruvic acid generated from the deamination of d-Ala catalyzed by d-amino acid oxidase, which is easily distinguished from l-form amino acids, d-Pro, and many other species. A linear concentration range is established from 20 to 400 μmol/L with a limit of detection of 1.01 μmol/L. Real saliva sample tests reveal that the levels of d-Ala in GC cases are remarkably higher than those in healthy individuals, which offers a simple and low-cost strategy for GC diagnosis. Simultaneously, the total concentrations of d-Ala and d-Pro in saliva are determined. Hence, the concentration of d-Pro and the proportion of d-Ala could be calculated, which further provides more molecule- and individual-specific information. This research may offer a convenient method for noninvasive diagnosis of GC and pave a new route to explore the potentials of rare d-form amino acids in disease diagnosis and treatment.
Chenyang Liu,Shuxiang Jiao,Yuhua Liu,Tao Wu,Leilei Xie,Lijuan Zhang,Yun Zhang,Wenming Wang,Hongfei Wang
Three isomeric nitrosylruthenium complexes [RuCl(Qn)(Pro)(NO)] ( 1 – 3) were prepared, where Qn is 8-hydroxyquinoline and Pro is D-proline. The complexes 1 – 3 were characterized by 1 H-NMR, 13 C-NMR, ESI-MS, and their crystal structure were further determined with X-ray diffraction techniques. In complexes 1 and 3 , the O atom of D-proline coordinated trans to NO, while the O atom of 8-quinolinol coordinated trans to NO in complexes 2 , and the complexes 1 and 3 are the Ru-centered enantiomers. The photo induced NO release of the complexes were explored using time-resolved infrared spectroscopy (FT-IR) and electron paramagnetic resonance spectroscopy (EPR) in solution and the released NO was successfully imaged in living cells using a NO selective fluorescent probe. Furthermore, the cytotoxicity of the isomeric complexes against HeLa, HepG2 and A549 cells were evaluated. Among them, the selectivity for HeLa cells is significant (SI ≥ 5) with IC 50 values in the range of 1.15–1.94 μM. Moreover, the three complexes spontaneously bind to human serum albumin (HSA) through hydrogen bonding and van der Waals forces, the binding constants K b of 1 – 3 are 1.528 × 10 4 , 2.390 × 10 4 and 2.694 × 10 4 M −1 at 298 K, respectively. Molecular docking analyses reveals that 1 – 3 bind within subdomain IB of the protein, which suggest that HSA could be a delivery vehicel for these complexes. This study provides insight into the potential biological and pharmaceutical applications for these isomeric nitrosylruthenium complexes.
Haiyan Fu,Ou Hu,Yao Fan,Ying Hu,Jiahao Huang,Zhao Wang,Yuanbin She
Interests in the recognition of chiral amino acids have grown tremendously in recent years, particularly in the fields of food analysis and pharmaceutical studies. Herein, an innovative “on-off-on” fluorescent assay has been developed for the sensitive and selective determination of chiral Proline (Pro), Lysine (Lys), and Serine (Ser). This detection platform is constructed by exploiting the fluorescence quenching ability of chiral self-assembly zinc 5, 10, 15, 20-tetra(4-pyridyl)-21 H -23 H -porphine (ZnTPyP) to CdTe quantum dots (CdTe QDs). CdTe QDs can act as signal switches whose fluorescence signals can effectively quenched by chiral nano ZnTPyP and then restored in the presence of enantiomer amino acids. The coupling use of CdTe QDs and chiral nano ZnTPyP also permits quantitative analysis of d -Pro, d -Lys, l -Ser with detection limits of 4.46 × 10 −10 mol L −1 , 7.13 × 10 −11 mol L −1 , and 3.35 × 10 −11 mol L −1 , respectively. The approach is also suitable for the effective detection of the three amino acids in complex biological matrices. This rapid, robust and reliable strategy for recognizing enantiomer amino acids has not been reported. The proposed method can be a powerful and valuable technology in the areas of drug discovery and food chemistry.
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